The energy company at the center of Dallas' gas drilling debate has threatened a Texas environmental group with a lawsuit over statements about a well-casing failure in Irving.

An attorney for Trinity East Energy sent the letter in late February to Zac Trahan at the Texas Campaign for the Environment, claiming Trahan made "verifiably false accusations" about the well-casing failure that Randy Lee Loftis documented earlier this month.

"Texas Campaign for the Environment ("TCE") is behind much of the opposition to drilling in the City of Dallas," states the letter from attorney Michael D. Anderson. "In that regard, TCE has disseminated many baseless and groundless attacks with the singular purpose of denying Trinity East's right to drill."

But the campaign reached a "new low" when Trahan suggested publicly that the well-casing failure "may have contaminated underground water aquifers," the letter states.

Trahan responded today in a letter defending his statements and letting Trinity East know that TCE will neither cease nor desist.

"It is, by now, well-known that the purpose of casing a well is to protect groundwater," Trahan wrote. "Thus, when a casing failure occurs, it is not unreasonable to question whether this casing failure has placed groundwater at risk for contamination."

According to Randy's report from public documents, the casing failed at a depth of 2,800 feet. Groundwater extended down to about 2,150 feet at the site, according to state analysis.

Public documents did not indicate whether there was any groundwater contamination.

But as Trahan points out in his letter, there is sparse information from Trinity East or the state Railroad Commission detailing the impact of the company's casing failure near the University of Dallas.

"If such analysis has been conducted, TCE welcomes the opportunity to review the results and report on them," Trahan writes.

Anderson's letter states flatly that there could not have been aquifer contamination at the site of the casing failure because the "surface casing was set and cemented at required depths...to protect all fresh water aquifers."

I reached Anderson this morning and he said he would contact his clients before commenting.

In Trahan's letter, issued today, he said the campaign won't be "deterred by the bullying tactics of Trinity East or others."

But he did offer Trinity East this concession.

"Nevertheless, in order to avoid any confusion, TCE is willing to issue the following supplemental information," he wrote.

"This gas company has already drilled a well along the Trinity River that had a casing failure beneath our underground aquifers. The company reported that no groundwater contamination occurred as a result in this instance. No independent testing was required to verify whether our aquifers are fully protected."